Methods and apparatus for load transfer in rotor assemblies

Abstract

A method of assembling a rotor assembly is provided. The method includes coupling a first turbine bucket to a rotor disk wherein the first turbine bucket includes a first tip shroud including a first surface, providing a second turbine bucket that includes a second tip shroud including a second surface, and coupling the second turbine bucket to the rotor disk such that the second turbine bucket is circumferentially adjacent to the first turbine bucket and such that during operation of the rotor assembly the first tip shroud contacts the second tip shroud along the first and second surfaces to enable at least one of a portion of radial loading induced to the first tip shroud to be transferred to the second tip shroud and a portion of radial loading induced to the second tip shroud to be transferred to the first tip shroud.

1 . A method of assembling a rotor assembly comprising:
 coupling a first turbine bucket to a rotor disk wherein the first turbine bucket includes a first tip shroud including a first surface;   providing a second turbine bucket that includes a second tip shroud including a second surface; and   coupling the second turbine bucket to the rotor disk such that the second turbine bucket is circumferentially adjacent to the first turbine bucket and such that during operation of the rotor assembly the first tip shroud contacts the second tip shroud along the first and second surfaces to enable at least one of a portion of radial loading induced to the first tip shroud to be transferred to the second tip shroud and a portion of radial loading induced to the second tip shroud to be transferred to the first tip shroud.   
   
   
       2 . A method in accordance with  claim 1  further comprises coupling the second turbine bucket to the rotor disk such that the second turbine bucket is circumferentially adjacent to the first turbine bucket and such that during operation of the rotor assembly, the first tip shroud contacts the second tip shroud along the first and second surfaces such that a portion of radial loading induced to the first tip shroud is transferred to the second tip shroud. 
   
   
       3 . A method in accordance with  claim 1  further comprises coupling the second turbine bucket to the rotor disk such that the second turbine bucket is circumferentially adjacent to the first turbine bucket and such that during operation of the rotor assembly, the first tip shroud contacts the second tip shroud along the first and second surfaces such that a portion of radial loading induced to the second tip shroud is transferred to the first tip shroud. 
   
   
       4 . A method in accordance with  claim 1  further comprises coupling the second turbine bucket to the rotor disk such that the second turbine bucket is circumferentially adjacent to the first turbine bucket and such that during operation of the rotor assembly, the first tip shroud contacts the second tip shroud along the first and second surfaces such that a portion of radial loading induced to the second tip shroud is transferred to the first tip shroud and a portion of radial loading induced to the first tip shroud is transferred to the second tip shroud. 
   
   
       5 . A method in accordance with  claim 1  wherein coupling the first turbine bucket to the rotor disk further comprises providing a first tip shroud that includes an undercut portion. 
   
   
       6 . A method in accordance with  claim 5  wherein providing the second turbine bucket further comprises providing a second tip shroud that includes an overhang portion that is configured to contact the first tip shroud undercut portion during rotor operation. 
   
   
       7 . A method in accordance with  claim 1  wherein coupling the second turbine bucket to the rotor disk further comprises positioning at least a portion of the first tip shroud surface radially inward of at least a portion of the second tip shroud second surface. 
   
   
       8 . A method in accordance with  claim 1  wherein coupling the second turbine bucket to the rotor disk further comprises positioning a portion of the first tip shroud first surface within a portion of the second tip shroud second surface. 
   
   
       9 . A method in accordance with  claim 1  wherein coupling the second turbine bucket to the rotor disk further comprises coupling the second turbine bucket to the rotor disk such that the first and second surfaces contact during operation of the rotor assembly wherein the second surface is positioned to resist radial outward movement of the first surface. 
   
   
       10 . A rotor assembly comprising:
 a first turbine bucket comprising a first tip shroud extending from a radially outer end of said first turbine bucket, said first tip shroud comprising a first surface; and   a second turbine bucket comprising a second tip shroud extending from a radially outer end of said second turbine bucket, said second tip shroud positioned circumferentially adjacent to said first tip shroud, said second tip shroud comprising a second surface configured to transfer at least one of a portion of radial loading induced to said second tip shroud to said first tip shroud and a portion of radial loading induced to said first tip shroud to said second tip shroud.   
   
   
       11 . An assembly in accordance with  claim 10  wherein at least a portion of said second surface is positioned radially inward of at least a portion of said first surface when said first turbine bucket and said second turbine bucket are coupled within said rotor assembly. 
   
   
       12 . An assembly in accordance with  claim 10  wherein said first surface is configured to be positioned within a portion of said second surface. 
   
   
       13 . An assembly in accordance with  claim 10  wherein said first surface comprises an overhang portion and said second surface comprises an undercut portion. 
   
   
       14 . An assembly in accordance with  claim 10  wherein said first surface and second surface are configured to mate substantially flush against each other during operation. 
   
   
       15 . A turbine bucket assembly comprising:
 a turbine bucket;   a tip shroud extending from a radially outer end of said turbine bucket, said tip shroud comprising a leading edge and an opposing trailing edge such that a first circumferential side and an opposing second circumferential side each extend between said leading edge and said trailing edge, said tip shroud further comprises at least one tip rail extending between said first circumferential side and said second circumferential side; and   a first surface and a second surface each extending along a portion of at least one of said first circumferential side, said at least one tip rail, said leading edge, and said trailing edge, said first and second surfaces are configured to enable radial load transfer.   
   
   
       16 . An assembly in accordance with  claim 15  wherein said first surface is an undercut portion, and said second surface is an overhang portion such that said undercut and said overhang portions facilitate radial load transfer. 
   
   
       17 . An assembly in accordance with  claim 15  wherein at least one of said first and second circumferential sides comprises said first surface and said second surface. 
   
   
       18 . An assembly in accordance with  claim 15  wherein said at least one tip rail comprises said first surface and said second surface. 
   
   
       19 . An assembly in accordance with  claim 15  wherein at least one of said leading edge and said trailing edge comprises said first surface and said second surface. 
   
   
       20 . An assembly in accordance with  claim 15  wherein said first surface is configured to be positioned within a portion of said second surface.